Detection of Quantitative Trait Loci

To apply major genes or linked markers in chicken marker assisted selection, they must first be identified and mapped on the chicken genome. The level of phenotypic variance accounted for such genes or linked markers in egg production and reproductive traits needs to be known. However, major genes and their variants which are responsible for egg production and reproductive traits have not been understood yet. Quantitative trait loci (QTL) mapping is the first step towards identification of genes affecting economically important traits. This book presents our findings on major QTLs affecting egg production and reproductive traits in reciprocal crosses generated from New Hampshire and White Leghorn lines that were kept at Humboldt Universitäte zu Berlin, Germany. The most interesting result from this study was the multiple QTLs mapped on chromosome 4 between 19.2 and 82.1 Mb. In this region, QTLs were mapped for number and weight of eggs, and body weight of hens. Egg weight was affected by two QTLs on chromosome 4 at 37.6 and 76.4 Mb. Therefore, this genomic region is an interesting interval for further fine mapping and candidate gene identification.